Sorting array using sort function returns error

Question

I have an array and I want to get the minimum of all stardates and maximum of all end dates. I am sorting the array first and then getting min and max of it. Below is the code.

var ticket_arr = '[{"Id":"a874062a-3f1e-4f91-a9d7-334aedd2e79f","Name":"Tesr","StartDate":"2015-04-08","EndDate":"2015-04-09","Duration":"1","leaf":true,"IsProject":false,"IsStage":false,"IsActivity":false,"IsTicket":true,"IsTask":false},{"Id":"19f3722f-5f19-430a-bf8a-699c6841aec2","Name":"Go define this test projecct","StartDate":"2015-04-21","EndDate":"2015-04-29","Duration":"8","leaf":true,"IsProject":false,"IsStage":false,"IsActivity":false,"IsTicket":true,"IsTask":false},{"Id":"5576edbf-3feb-4204-b488-0d0a35688538","Name":"Mike is getting a lesson in cool","StartDate":"2015-04-08","EndDate":"2015-04-10","Duration":"2","leaf":true,"IsProject":false,"IsStage":false,"IsActivity":false,"IsTicket":true,"IsTask":false},{"Id":"5bf5d77c-73b1-480b-8758-2e822db73964","Name":"Test ticket","StartDate":"2015-04-08","EndDate":"2015-04-09","Duration":"1","leaf":true,"IsProject":false,"IsStage":false,"IsActivity":false,"IsTicket":true,"IsTask":false}]';

function sortArray(arr, name){
    arr.sort(function(a,b) 
        {
      if (new Date(a[name]) > new Date(b[name]) )
         return 1;
      else if (new Date(a[name]) < new Date(b[name]) )
         return -1;
       else
         return 0;
    }); 
}
function getMinMaxDate(arr, name, type)
{
    if(arr.length)
    {
        sortArray(arr, name);
        console.log(arr);
        console.log(name);
        if(type == "Min" && arr.length)
        {
                        console.log(arr[0][name]);
            return arr[0][name];
        }

        if(type == "Max" && arr.length)
        {
            return arr[arr.length-1][name];
        }
    }
    else
        return '';
}

But the code gives an error that says arr.sort is not a function.

Answer 1

That's because ticket_arr isn't an array, it's a string. Fix that either by removing the single quotes around the value:

var ticket_arr = [{"Id":"a874062a-3f1e-4f91-a9d7-334aedd2e79f","Name":"Tesr","StartDate":"2015-04-08","EndDate":"2015-04-09","Duration":"1","leaf":true,"IsProject":false,"IsStage":false,"IsActivity":false,"IsTicket":true,"IsTask":false},{"Id":"19f3722f-5f19-430a-bf8a-699c6841aec2","Name":"Go define this test projecct","StartDate":"2015-04-21","EndDate":"2015-04-29","Duration":"8","leaf":true,"IsProject":false,"IsStage":false,"IsActivity":false,"IsTicket":true,"IsTask":false},{"Id":"5576edbf-3feb-4204-b488-0d0a35688538","Name":"Mike is getting a lesson in cool","StartDate":"2015-04-08","EndDate":"2015-04-10","Duration":"2","leaf":true,"IsProject":false,"IsStage":false,"IsActivity":false,"IsTicket":true,"IsTask":false},{"Id":"5bf5d77c-73b1-480b-8758-2e822db73964","Name":"Test ticket","StartDate":"2015-04-08","EndDate":"2015-04-09","Duration":"1","leaf":true,"IsProject":false,"IsStage":false,"IsActivity":false,"IsTicket":true,"IsTask":false}];

Or, if it's loaded via AJAX or generated on the client side, by parsing it as JSON:

var ticket_arr = JSON.parse('[{"Id":"a874062a-3f1e-4f91-a9d7-334aedd2e79f","Name":"Tesr","StartDate":"2015-04-08","EndDate":"2015-04-09","Duration":"1","leaf":true,"IsProject":false,"IsStage":false,"IsActivity":false,"IsTicket":true,"IsTask":false},{"Id":"19f3722f-5f19-430a-bf8a-699c6841aec2","Name":"Go define this test projecct","StartDate":"2015-04-21","EndDate":"2015-04-29","Duration":"8","leaf":true,"IsProject":false,"IsStage":false,"IsActivity":false,"IsTicket":true,"IsTask":false},{"Id":"5576edbf-3feb-4204-b488-0d0a35688538","Name":"Mike is getting a lesson in cool","StartDate":"2015-04-08","EndDate":"2015-04-10","Duration":"2","leaf":true,"IsProject":false,"IsStage":false,"IsActivity":false,"IsTicket":true,"IsTask":false},{"Id":"5bf5d77c-73b1-480b-8758-2e822db73964","Name":"Test ticket","StartDate":"2015-04-08","EndDate":"2015-04-09","Duration":"1","leaf":true,"IsProject":false,"IsStage":false,"IsActivity":false,"IsTicket":true,"IsTask":false}]');

(If you intend to use JSON.parse on older browsers, such as IE7-, you'll need a polyfill. JSON 3 is a well-known one.)